network: Make vdsmd delNetwork use supervdsmd setupNetworks

delNetwork is part of a very old and deprecated API that we have to
eventually shed off in the next major release. It makes sense to
just make an adapter so that we can simplify network.api to keep
a single entry point.

Change-Id: Ic1ddb7bdd2128c35a3d8198a5ca2850aea974c38
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Signed-off-by: Ido Barkan <ibarkan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/35310
Reviewed-by: Dan Kenigsberg <danken@redhat.com>